The centralizer with double segmental spring leafs is the variety of one with single segmental spring leaf and has both elastic and rigid characters.

 
  • 雙弓形彈簧片套管扶正器是單弓形的變異,它具有彈性扶正器的優(yōu)點(diǎn),又有剛性的特點(diǎn)。
今日熱詞
目錄 附錄 查詞歷史
国内精品美女A∨在线播放xuan